1. Field of the Invention
The invention relates to a plug connector with an insulated contact holder and a contact element movably mounted within the contact holder. The plug connectors may be multiple pole or contact electrical connectors designed as mating plugs and sockets.
2. Description of the Related Technology
Plug connectors may be used to connect electrical contact elements. Plug connectors are advantageous as they exhibit contact elements arranged in a floating layout, such as plug sockets. Plug connectors allow one to avoid the use of "riders" of the plug pins, even when an undesirable summation of tolerances occurs.
The undesirable summation of tolerances may result from manufacturing tolerances inherent to injection molding process and shape and position tolerances of the contact holder and contact elements, which may not be avoided. Using "riders" with the plug pins on or even adjacent to the socket walls is disadvantageous and may lead to damage to and/or malfunctioning of the contact elements.
Constructive solutions are known for equalization or compensation of tolerances between the socket and the corresponding plug contacts, as shown in FIG. 1a through 1c.
FIG. 1a shows a known embodiment of a plug connector with a contact chamber 3 and a floating contact element 1. A shoulder 4 of the floating contact element is located in an expanded recess 2 of the contact chamber. The axial and radial dimensions of the shoulder are smaller than the dimensions of recess 2. A cover plate 5 secures contact element 1 and prevents the contact element from dropping out of the plug connector.
The contact element may include a shaft 6 located on a conduit connecting side and a plug side of the contact element. The shaft 6 passes through a bore hole 7 in cover plate 5. The internal diameter of bore hole 7 is larger than the diameter of shaft 6, as is the internal diameter of the contact chamber 3 on the plug side. Contact element 1 may be displaced in the contact holder 5, 8 in both the radial and axial directions and inclined relative to the plug axis. Large tolerances may be compensated in this manner, as a result of proper dimensions of the parts.
The plug connector may suffer from several drawbacks. The contact holder with the necessary cover plate is expensive to manufacture. Further, the cover plate must be securely fastened to the contact holder in order to withstand the contact pressure. Additionally, there are costs involved in mounting the cover plate, particularly in the case of multi-pole plug connectors, as the contact parts on the connecting side are not always in the correct position relative to the corresponding recesses in the cover plate. Another limitation in the prior configuration is that the contact is not embedded in the contact holder 5, 8 in a water tight fashion. Accordingly, this configuration has a restricted field of application.
As shown in FIG. 1b, locking flaps 10 are provided to secure the contact element 9. When the contact element 9 is inserted in the contact chamber 11, the locking flaps abut against the shoulder on the plug side of the collar 12. Large tolerances may also be equalized or compensated with this plug connector.
This configuration also suffers from the above-mentioned drawbacks. A disadvantage is that the contact holder 13, 14 must be formed from two parts. The requirement of stripping the parts from an injection molding machine constrains the configuration to a two-part system.
FIG. 1c shows an alternative plug connector including a contact chamber 16 defined by a one-piece contact holder 17. As shown in FIG. 1c, the contact element 15 is secured in a terminal area of the contact chamber 16 on the plug side. The contact includes a thickened segment 18 and a safety collar 19 in order to secure the element. A thin bending zone 20 enhances the mobility of the contact element 15. Even in this configuration the mobility of the contact element and thus the range of tolerance equalization is limited. Considerations such as space availability and the constant practical requirement for a low electrical resistance necessitate that the bending zone must be short and cannot be very thin.
A plug connector according to this layout requires the application of a large force to bend the contact element during the insertion process. The use of a large force may render the insertion very difficult or even impossible when the plug connector includes a large number of poles. In addition, the use of a large force results in a point shaped contact between the pin and the socket, with an associated high passage or contact resistance.